I would like to check in, please.
vor-REI — stress on the second syllable. The 'ei' is a diphthong, not two separate sounds.
A polite opener when approaching the front desk, especially if there is no queue and you want to state your intention clearly.
'Vorrei' is the conditional of 'volere' (to want) and is the Italian equivalent of 'I would like' — far more polite than 'voglio' (I want). Using the conditional tense in requests is considered essential good manners in formal Italian settings.
Posso fare il check-in?
Can I check in?
Slightly more direct but still polite
Sono qui per il check-in.
I am here to check in.
Very straightforward, used when the context is already clear
A che ora posso fare il check-in?
What time can I check in?
Ask this if you are arriving early and are not sure of the hotel's policy
Standard check-in time at Italian hotels is 3pm (15:00). If you arrive earlier, luggage can usually be stored at the front desk free of charge while you explore the city.